A spectrum is an extremely expensive resource in wireless communication. Modern communications systems, such as a Global System for Mobile Communications (GSM) system, a Code Division Multiple Access (CDMA) 2000/Wideband CDMA (WCDMA) system, and a Long Term Evolution (LTE) system, generally operate on a carrier frequency below 3 gigahertz (GHz). With popularity of intelligent terminals, especially emergence of video services, it is difficult for current spectrum resources to meet an explosively-increasing requirement of a user for a capacity. A high frequency band with a larger available bandwidth, especially a millimeter-wave band, gradually becomes a candidate frequency band of a next generation communications system. For example, within a range of 3 GHz to 200 GHz, a potential available bandwidth is approximately 250 GHz. In addition, a multiple-antenna technology is usually used in the modern communications system to improve a capacity and coverage of the system or to improve user experience. Another advantage brought using the high frequency band is as follows. A size of multiple configured antennas can be greatly reduced in order to facilitate site obtaining and deployment of more antennas. However, the high frequency band results in a larger path loss, and especially, impact of factors such as an atmosphere and vegetation further exacerbates a wireless propagation loss.
For transmission of an uplink sounding reference signal (SRS) of a user to overcome the larger path loss, usually larger transmit power needs to be set to compensate for a large loss in a high-frequency propagation process. Due to the larger path loss, a cell-edge user needs the larger transmit power or even full power to resolve a problem that coverage of the user is limited. Because power is limited, the user can send an SRS only using a smaller user-specific SRS bandwidth. In addition, in a high frequency, as a system bandwidth increases, a quantity of resource blocks (RBs) corresponding to the system bandwidth multiplies. For example, corresponding quantities of RBs used when the system bandwidth is 500 megabytes (MB) and 1 gigabyte (GB) are respectively 2.5 times and 5 times a quantity of RBs used when the system bandwidth is 10 MB. In time division duplex (TDD) that is used as a mainstream multiple access multiplexing manner in a high frequency, a base station may obtain, by means of measurement, channel quality on an entire downlink system bandwidth according to reciprocity of uplink and downlink channels using uplink SRS channel quality.
However, in an uplink reference signal transmission manner used in other approaches, when a user-specific SRS bandwidth configured by a user is relatively small, efficiency of full-bandwidth channel quality measurement of a system is relatively low.